Displays in image display devices, such as television devices, are now being shifted from conventional cathode-ray tube displays to thin displays, such as liquid crystal displays and plasma displays. Liquid crystal panels do not emit light. If the liquid crystal panels are used as display components in the liquid crystal display devices, backlight devices are required as separate lighting devices.
Patent Document 1 discloses a transmissive backlight device including a back chassis, alight source block, a diffusion light guide plate, a reflection sheet, and a plurality of optical stud members. The light source block is mounted on the back chassis. The reflection sheet reflects light toward the diffusion light guide plate. The optical stud members are mounted on the back chassis. Distal end portions of the optical members are held against the diffusion light guide plate to regulate a distance between the diffusion light guide plate and the reflection sheet and a distance between the reflection sheet and the back chassis. In such a backlight device, the optical stud members (supporting pins) may restrict the diffusion light guide plate (an optical member) from bending toward the back chassis. Further, the optical stud members may position the diffusion guide plate with high accuracy in the backlight chassis. As a result, uneven brightness is less likely to occur.